package com.example.demo.offer;

import java.util.Deque;
import java.util.LinkedList;

public class Offer25 {
    public static void main(String[] args) {

    }

    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        Deque<Integer> stack1 = new LinkedList();
        Deque<Integer> stack2 = new LinkedList();
        while (l1 != null){
            stack1.push(l1.val);
            l1 = l1.next;
        }
        while (l2 != null){
            stack2.push(l2.val);
            l2 = l2.next;
        }
        int carry = 0;
        ListNode ans = null;
        while (!stack1.isEmpty() || !stack2.isEmpty() || carry != 0){
            int a = stack1.isEmpty() ? 0 : stack1.pop();
            int b = stack2.isEmpty() ? 0 : stack2.pop();
            int sum = a + b + carry;
            carry = sum / 10;
            sum %= 10;
            ListNode listNode = new ListNode(sum);
            listNode.next = ans;
            ans = listNode;
        }
        return ans;
    }

}
